struggling through some obscure Java code

I think I really like programming. In Java, of course.
But sometimes I fell kind of frustrated when I can't understand what
exactly the code is supposed to do. This is why the Javacode was
invented: to help those who read your code after you understand it
clearly.
For some reason, those who wrote the code I am modifying now either
didn't know how to write a good Javacode or didn't want to make the life
of others easier.
Just for example, how a Javacode like this can possibly help anybody? :
/**
* someCalculationMethod <br>
*
* @exception SomeException
**/
public void someCalculationMethod throws SomeException(){
}
Why couldn't you write in what it does, when and how???